1. Invention Field
The present invention relates to underwater trenching systems, and more particularly to a self-guiding system for trenching water bottoms for the installation of a pipeline. The preferred embodiment of the present invention teaches a system which is configured to be mounted about the pipeline to be buried, and which further contemplates a uniquely configured, forward mounted trenching/drive mechanism incorporating a cutter wheel generally about the width of the desired trench, the mechanism configured to propel the system as well as trench the desired area.
The trenching/drive mechanism of the present invention further includes a high pressure spray array mounted about the frontal cutter wheel area, and a suction/mud pump assembly to the rear of the cutter wheel. The high pressure spray array provides the dual purpose function of loosening the area to be trenched, as well as cleaning and removing the trenched matter from the cutter wheel.
The present invention further includes first and second buoyancy chambers which are configured to be uniformly lowered to the lower periphery of the unit frame, to provide skids for utilization of the present system in shallow water.
An alternative embodiment of the present invention teaches the incorporation of a framed system similar to that as taught in the present invention, but without the trenching/drive mechanism, and with the addition of a pipe cutter mounted to the rear of the unit frame, for utilization of pipeline recovery and dismemberment operations.
2. General Background Discussion
While the prior art may have contemplated a variety of underwater trenching systems for utilization in conjunction with laying pipe and related operations, none are believed to have contemplated the combination trencher/drive system of the cutter mechanism contemplated by the present invention.
A list of prior patents which may be of interest is presented below:
______________________________________ Patent No. Patentee(s) Issue Date ______________________________________ (Plough Trenchers): 4992000 Doleshal 02/12/91 4980097 Lynch 01/22/91 4410297 Lynch 10/18/83 4245927 Wharton 01/20/81 4091629 Gunn et al 05/30/78 (Cutter Wheel Trenchers/Dredges): 4416014 Satterwhite 09/26/78 4301606 Hofmeester 11/24/81 4329087 Satterwhite 05/11/82 4314414 Reynolds et al 02/09/82 4470720 Lennard 09/11/84 4149326 Rosa et al 04/17/79 3023586 Morrison 03/06/62 0708583 Powell 09/09/02 0941050 Sykes 11/23/09 3605296 Dysart 09/20/71 1220197 Cowles 03/27/17 0814270 Burch 03/06/06 0737021 Roberts 08/25/03 0141752 Boschke 08/12/73 0171380 Hawley 12/21/1875 0158717 Kuhn 01/12/1875 (Trenchers with Lateral Cutting Members): 4280289 Bassompierre-Sewrin 06/28/81 4274760 Norman 06/23/81 4022028 Martin 05/10/77 4714378 Lincoln 12/22/87 4516880 Martin 05/14/85 4117689 Martin 01/03/78 4087981 Norman 05/09/78 4044566 Biberg 08/30/77 3995439 Hahlbrock 12/07/76 3887237 Norman 04/15/75 3670514 Breston et al 06/20/72 3583170 DeVries 06/08/71 (Movable Bit Trencher): 3978679 Lecomte 09/07/76 (Fixed Propeller Trencher): 3004392 Symmank 10/17/61 ______________________________________
The prior art contemplates various systems for trenching, including for the installation of pipelines, including the following general categories:
A. Plough Trenchers PA1 B. Cutter Wheel Trenchers/Dredges PA1 C. Trenchers with Lateral Cutter Members PA1 D. Movable Bit Trenchers PA1 E. Fixed Propeller Trenchers
The present, searched for invention, as described above, teaches a system for excavating a trench for the burial of a pipeline incorporating many components as set forth in the patents cited herein.
Referring to category "A", U.S. Pat. No. 4,992,000 teaches a trenching sled which includes forward jets for loosening the area, and a rearwardly directed suction means for removing the trenched material.
Referring to category "B", U.S. Pat. No. 4,301,606 issued 1981 to Netherlands Offshore Co. teaches a underwater trenching apparatus for pipelines utilizing a cutter wheel (15) and water jets (24) for loosening the trenched material and ready situated suction (22) for removing said trenched material.
U.S. Pat. No. 4,374,760 in Category "C" teaches a "Self Propelled Underwater Trenching Apparatus . . ." to Norman which teaches a drive system which may have some general pertinence to the anode jumper system of the present invention.
U.S. Pat. No. 4,280,289 teaches another trencher which utilizes lateral cutter members, claiming a means of manipulating the rollers to avoid obstacles.
As may be denoted by a review of the above, there have been several machines configured to dig a trench in the bottom of the water to bury pipe, cables, etc. However, unlike the prior art, the present invention has a unique cutter mechanism which provides propulsion or driving means during operation.